Methylamine extaction methods

Friendlycat · Fri Jun 10, 2005 6:41 am

Hi there!

Swim wants to extract Mehn2.HCl with Butanol as easily as possible keeping purity and yield high without going Orange.

Swim added 50g Hex + 155g 30% HCl + methanol + 10g NH4CL set up in a 3 neck 250ml RBF with a packed 250 mm column in a mantle. The methyl formate was distilled over about 3 hours, temp around 31.5 to 36 deg C (I think, can't remember right now). heat was progressivly raised while distilling formate until the reaction temp reached 90 deg C and was kept there for 1 hour. Cooled, filtered, set up in water bath with simple vacuum distilation. reduced till Nh4CL spotted, cooled, filtered, reduced again till very thick and mushy and no more distillate come over.

Now swim is thinking of extracting either of 3 ways;

1) Adding butanol, fractionally distilling azeotrope till dry, decanting then adding fresh dry butanol and simply boiling and decanting. With oil bath at 145 deg C.

2) Adding butanol, boiling decanting, etc pooling, cooling, filtering, distilling the butanol to crash out MeNh2.HCl.

3) The more traditinal method of cooling before it's gets mushy, filtering to collect the MeNH2.HCl and returning filtrate, reducing and pouring into a beaker where it goes solid, then boiling with butanol.

Swim's amine turned orange when using method (1) and no amine collected. That happened in another synth where more HCL was used (100g Hex + 330g HCl) Can too much HCl screw things up? Why did it turn orange?

Regards,
FC